Printing needle drive

ABSTRACT

In a wire printer, in which a plurality of selected printing needles are simultaneously advanced to print a character, each printing needle is operated by a lever to which the plunger armature of an electromagnet is secured at a smaller distance from the lever fulcrum than the printing needle so that the needle stroke is greater and faster than the armature stroke. The lever is preferably resilient, and the mass of the needle is selected so that upon actuation of the armature, the lever is at first slowed down by the mass of the printing needle and then recoils to move at a higher speed than the armature, and to continue in a free stroke when the armature is stopped at the end of the armature stroke. Preferably, the attaching end portion of the wire which forms the printing needle, is wound in a coil around the lever to permit resilient yielding of the printing needle when abutting a printing surface at the end of the needle stroke.

United States Patent 1 91 Heindke et al.

[ 51 July 1,1975

[ PRINTING NEEDLE DRIVE [73] Assignee: Kienzle Apparte GmbH, Villingen,

Germany [22] Filed: June 14, I973 [21] Appl. No.: 370,059

[30] Foreign Application Priority Data June 23, 1972 Germany 2230810[52] US. Cl l0l/93.05; 197/1 R; 335/230 [5 I] Int. Cl. B4lj 3/10; H0lf7/08 [58] Field of Search 197/1 R; 101/93 R, 1 R, 101/93 MN, 93.05;335/230, 324

[56] References Cited UNITED STATES PATENTS 3,099,711 7/1963 Foley eta1. 197/1 R 3,217,640 11/1965 Bradshaw 197/1 R 3,266,418 8/1966 Russo197/1 R 3,333,667 8/1967 Nordin 197/1 R 3,561,355 2/1971 Rapparlie et a1197/1 R 3,672,482 6/1972 Brumbaugh 197/1 R 3,770,092 11/1973 Grim 197/1R 3,775,714 11/1973 Heuer 197/1 R FOREIGN PATENTS OR APPLICATIONS646,886 8/1937 Germany 197]] R 1,577,409 8/1969 France 197/1 R 1,244,7949/1960 France 197/1 R 1,254,388 11/1967 Germany.... 197/1 R 1,270,8586/1968 Germany.... 197/1 R 1,270,859 6/1968 Germany 197]] R PrimaryExaminer-E. H. Eickholt Attorney, Agent, or Firm-Michael S. Striker [57] ABSTRACT In a wire printer, in which a plurality of selected printingneedles are simultaneously advanced to print a character, each printingneedle is operated by a lever to which the plunger armature of anelectromagnet is secured at a smaller distance from the lever fulcrumthan the printing needle so that the needle stroke is greater and fasterthan the armature stroke. The lever is preferably resilient, and themass of the needle is selected so that upon actuation of the armature,the lever is at first slowed down by the mass of the printing needle andthen recoils to move at a higher speed than the armature, and tocontinue in a free stroke when the armature is stopped at the end of thearmature stroke. Preferably, the attaching end portion of the wire whichforms the printing needle, is wound in a coil around the lever to permitresilient yielding of the printing needle when abutting a printingsurface at the end of the needle stroke.

13 Claims, 6 Drawing Figures 1 PRINTING NEEDLE DRIVE BACKGROUND OF THElNVENTlON The present invention relates to a wire printer or needleprinter in which the characters to be printed are formed by a pluralityof points printed by printing wires or needles. Matrix printers areknown in which, for example, 5 times 7 needles are arranged in lines andcolumns in the printing head, and selectively operated to form and printthe desired character. After a tabulating step, the next character isprinted in the same manner. Another wire printer is known in which onlyseven needles are mounted in the printing head, which are arranged in acolumn at right angles to the line direction. A character to be printedis formed in several steps of the printing head, the selected printingneedles of the columns being operated after each step so that after forexample, five steps, a character is completed. After correspondingspacing steps by which the normal spacing between characters isobtained, the printing of the next following character is carried out inthe same manner.

Modern wire printers of this type use an electromagnet for actuatingeach printing needle or wire. When the electromagnet is energized, therespective needle is rapidly advanced out of an initial position of restto a printing position abutting the ink ribbon, and producing imprintson a paper sheet, and if desired on carbon copies, as disclosed, forexample, in the German OS 1,943,675.

The printing needles or wires are substantially straight, or slightlybent toward the respective electromagnets, and partly guided in guidetubes, so that a rigid connection is formed between the printing surfaceand the armature of the electromagnet when the printing operation iscarried out. This requires an extremely precise adjustment of theprinting needle stroke, since otherwise, if the stroke is too long, theink ribbon and even the paper sheet is perforated, or if the needlestroke is too short, only a weak impression or no impression at all ismade. If the needle stroke is far too great, excessive bending andbuckling forces are produced, which may cause breakage of the needle.Particularly, at high printing frequencies, the danger of breakage ofthe needles due to oscillations is great.

The German AS 1,270,858 discloses a printer of this type in which theprinting needle is connected with the armature by a hook and eyeconnection providing some lost motion. However, this arrangement has notbeen fully successful.

The German Pat. No. 1,270,859 discloses an arrangement in which thearmature of the electromagnet is tiltable and provided with an elasticarm on which the rear end of the printing needle abuts. Since the arm iselastic, the connection between the armature and the printing needle isnot rigid, but the frequency of the needle actuations is substantiallyreduced because a tiltable armature has a very low efficiency due to theinherently large stray field, as compared with a plunger armature. Tocompensate this disadvantage a slot and pin connection between theprinting needle and the armature is used.

SUMMARY OF THE INVENTION It is an object of the invention to provide animproved printing needle drive which operates at high ef- 2 ficiency andis capable of operating the printing needles at a high speed.

Another object of the invention is to combine the high efficiency of anelectromagnet with a plunger armature, with transmission of motion fromthe armature to the printing needle by resilient means.

Another object of the invention is to connect the armature with therespective printing needles by a lever in such a manner that thearmature stroke is shorter than the printing needle stroke.

Another object of the invention is to mount the printing needle onresilient means, so that breakage due to a rigid connection between thearmature and the printing needle is avoided.

Another object of the invention is to connect an armature by means of aresilient lever with the printing needle to obtain free movement of theprinting needle due to elastic recoil when the armature is stopped atthe end of its stroke.

Another object of the invention is to provide a formlocking connectionbetween the printing wire and the respective armature.

With these objects in view, an embodiment of the invention compriseslever means having a fulcrum; a printing needle means secured to a firstportion of the lever means; electromagnetic means including a movablearmature connected with a second portion of the lever means spaced fromthe fulcrum a smaller distance than the first portion so that when thearmature is moved in an armature stroke of predetermined length, theneedle means is moved in a needle stroke of proportionally greaterlength, and at a higher speed than the armature. [n the preferredembodiment of the invention, pivot means are provided at one end of thelever means, the first portion is an end portion located at the otherend of the lever means and the armature is connected with the secondportion intermediate the ends of the second lever means. Preferably, thearmature is a plunger armature movable in an annular winding and havinga portion projecting from the winding and secured to the second portionof the lever means.

In the preferred embodiment of the invention, the lever means isresilient, and the mass of the needle means has such a predeterminedmagnitude to momentarily prevent movement of the first portion duringthe first part of the armature stroke by the resilient lever meansresiliently deforms and is tensioned so that the lever means recoilsduring the second part of the armature stroke and accelerates the needlemeans faster than the armature is accelerated.

A stop means is provided for stopping the armature at the end of thearmature stroke so that the recoiling resilient lever means continues tomove the needle means in a free needle stroke after the stop means hasstopped the armature.

The printing needle means preferably includes a wire having a projectingprinting end portion, and a resilient attaching end portion wound in acoil surrounding the end portion of the lever means.

It is particularly advantageous to provide a wire including anintermediate portion between the printing end portion and the coil. Theprinting end portion is located in an imaginary line passing through theaxis of the coil, and the intermediate portion is cranked out of theimaginary line and extends tangentially to the first turn of the coil sothat the same spreads when the printing end portion abuts a printingsurface.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation. together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is an axial sectional viewillustrating an embodiment of a printing needle drive according to theinvention;

FIG. 2 is a side view illustrating one printing needle;

FIG. 3 is a plan view illustrating the printing needle of FIG. 2; and

FIGS. 4a, 4b and 4c are fragmentary sectional views illustratingsuccessive positions of the armature and needle means during a printingoperation.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. I, anelectromagnet 1 includes an annular or tubular winding Ia surrounding aplunger armature 2 and a fixed core I forming a stop a for the axiallymovable armature 2. A return spring 9 is mounted on a supporting frame40 and passes through a bore in the end portion 3 of armature 2 so thatarmature 2 is biased to a position abutting an adjustable screw 4threaded into the supporting frame 40 and secured by a nut 5. Whenwinding la is energized, the plunger armature is pulled against theaction of spring 9 until abutting the stop portion 10a of the fixed core10.

In addition to the bore 3b, the end portion 3 of armature 2 has a bore3a through which the portion 6b of the elastic lever 6 passes. A member7a is secured to one end of lever 6 and carries a pivot pin 7b mountedon a bracket 41 of the supporting means so that lever 6 is turnableabout the fulcrum formed by the pivot 7b. The other end of lever 6 hasan end portion 6a to which a printing needle 8 is attached by aform-locking connection. The printing needle portion 8b is only partlyshown in FIG. 1, and it will be understood that the printing endportions 8b of a plurality of printing needles are combined in aprinting head for printing points which together form a character. Theprinting head has bores for guiding the printing end portions 8b,respectively, during the printing stroke.

When the winding la is energized, the armature 2 is drawn into theelectromagnet l, tensioning the return spring 9 and moving the lever 6.The downward arma' ture stroke of armature 2 as viewed in the drawing,is limited by the stop portion 10a of the fixed iron core 10, and ispreferably 0.4 mm. Since the center portion 6b of lever 6 moves the samedistance as the armature 2, its end portion 6a moves a distance of 0.8mm. taking along the printing needle 8, so that the needle stroke istwice as great than the armature stroke due to the fact that thedistance between the armature 3 and the pivot 7b is only half thedistance between the lever end portion 6a and the pivot means 7b. Inthis manner a small armature stroke results in a larger printing strokeof the printing needle 8, and in a high speed of the needle movement. Asa result, the armature stroke can be very small, which permits a veryhigh frequency of the armature strokes.

As shown in FIGS. 1 and 2, the printing needle 8 has a resilientattaching portion which is constituted by a coil 8a formed of the wirewhich ends in the printing needle 8. The wire of the printing needle 8is preferably formed as shown in FIGS. 2 and 3, whereupon the coil 8a ispushed onto the free end portion 6a of lever 6, so that the needle 8 isconnected with the lever 6 for performing the printing stroke, althoughremoval of the printing needle wire 8 from the end portion 6a ispossible in axial direction. The resilient pressure of the coil 8a onthe lever end portion 6a secures the printing needle to lever 6.

As shown in FIG. 3, the printing needle 8 preferably has a straightprinting needle portion 8b located on an imaginary line 8d passingthrough the axis of the coil 8a. The intermediate portion 8c is crankedout of the imaginary line 8d, and tangentially connected with the firstturn of the coil 8a, as best seen in FIG. 3. Consequently, the firstturn of the coil 8a resiliently yields when the leading end of theprinting needle 8 impinges the printing surface or the ink ribbon. Theresilient mounting of the printing needle 8 on the lever 6 permits theimpingement of the printing needle portions 8b on a steel plate, withoutany damage to the printing needle 8.

However, it has been found that at a very high printing speed andfrequency of the needle operations, breakage may occur in the firstturns of the wire coil 8a, and to overcome this defect, coil 80, and theintermediate portion of the printing needle 8 are embedded in a jacketconsisting of a synthetic plastic mass which has only little influenceon the resiliency of the coil 80, but prevents undesired oscillations.

In the preferred embodiment of the invention, the lever 6 is a rodconsisting of spring steel so that the clasticity of the connectionbetween the driving armature 2, 3 and the printing needle end portion 8is increased.

FIGS. 40, 4b and 4c show the positions of the above described partsduring an operation. FIG. 4a shows an initial position of rest in whichthe end portion 3 of the armature 2 abuts the adjusting screw 4,resilient lever 6 is not deformed, and the jacket ll abuts the dampingmember I2 which is secured to the supporting frame 3, as also shown inFIG. 1. The inner end of the armature 2 is spaced from the stop portion104 of core 10.

When the winding la of the electromagnet 1 is energized, the armature 2moves rapidly into the annular winding la. The mass of members 8 and II,and the resiliency of lever 6 are selected, so that during the firstpart of the stroke of the armature 2,3, the lever 6 is resiliently bent,while the lever end portion 6a momentarily remains in the same positionwhereby the lever 6 is resiliently deformed and tensioned. Thereupon thelever 6 recoils and rapidly accelerates the printing needle 8 toward theprinting surface during the second part of the armature stroke. When thearmature 2 abuts stop portion as shown in FIG. 4c, the printing needle 8with the coil spring 80 and the end portion 6a of the resilient lever 6move due to inertia in a free movement toward the end of the printingstroke independently of, and beyond the armature strokes. In thismanner, a further increase of the needle stroke of the printing strokeof the needle 8 from 0.8 mm. to 1 mm. is obtained.

FIGv 4c schematically shows the positions of the parts in the moment ofimpact of the printing needle on the printing surface.

Due to the free flight of the printing needle 8 at the end of theprinting stroke, lever 6 is tensioned when the printing end portion 8bhas impinged on the printing surface, but this time in the oppositedirection than before described with reference to FIG. 4b. Due to theelastic tension in lever 6 in the position shown in FIG. 40, after theimpinging of the printing needle 8 on the printing surface, the returnforce of resilient lever 6 is added to the force applied by the returnspring 9 on the armature 2, 3 so that the printing needle 8 is furtheraccelerated during the return stroke.

However, such acceleration during the return stroke of the printingneedle 8 is desirable only at the beginning of the return stroke ofprinting needle 8, and the energy stored in the resilient lever 6 mustbe dissipated when the initial position of rest, shown in H6. 4a, isobtained, so that undesirable oscillations of the drive are prevented.For dampening such oscillations, a damping member I2 is secured to thesupporting means 40 adjacent the end portion 6a of lever 6 andcooperating with the jacket 1] which envelops the coil 80. At the end ofthe return movement, the printing needle 8 with the coil 8a and thejacket 11 impinges the stationary damping member 12 which preferablyconsists of a foam plastic material, or similar damping material. Thedamping member must be designed and selected to prevent recoil of thearmature 2 when its end portion 3 impinges the adjusting screw 4.

Due to the elasticity of lever 6, together with the high efficiency ofthe plunger armature 2 surrounded by winding la, an accelerated advanceof the printing needle 8 is obtained, which, due to the resiliency ofthe lever 6, results in a free flight of the printing needle toward theprinting surface at the end of the needle stroke. The cooperation ofelements 2, 6, 8a, and 8 in the illustrated embodiment of the invention,results in a substantial increase of the frequency of the printingstrokes of the needles, and in a relatively great needle stroke, whilethe danger of breakage of the printing needles 8 is substantiallyreduced as compared with known needle or wire printers. The printingneedle drive of the invention can be advantageously applied to all kindsof modifications of matrix printers, point printers, and other wireprinters in which a printing head, guiding a plurality of printingneedles, is used for forming characters of printed dots.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofprinting needle drives differing from the types described above.

While the invention has been illustrated and described as embodied in aprinting needle drive in which the effective lever arm of the needle isgreater than the effective lever arm of an armature, so that theprinting needle moves at a higher speed than the armature, and in whichresilient means produce free needle movements due to inertia andindependent of the movement of the armature, it is not intended to belimited to the details shown, since various modifications and structuralchanges may be made without departing in any way from the spirit of thepresent invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims.

We claim:

1. Printing needle drive comprising supporting means; elongated levermeans having a fulcrum mounted on said supporting means and being formedover the whole length thereof from resilient material; printing needlemeans secured to a first portion of said lever means and projectingtherefrom transversely to said lever means; and electromagnetic meansincluding a movable armature connected with a second portion of saidlever means spaced from said fulcrum a smaller distance than said firstportion so that when said armature is moved in an armature stroke ofpredetermined length, said needle means is moved in a needle stroke ofproportionally greater length, and at a higher speed than said armature,the mass of said needle means having a predetermined magnitude toprevent movement of said first portion of said lever means during thefirst part of said armature stroke whereby said resilient lever means isresiliently deformed and tensioned so that said resilient lever meansrecoils during the second part of said armature stroke and acceleratessaid needle means faster than said armature is accelerated when saidelectromagnet means is energized.

2. Printing needle drive as claimed in claim I wherein said supportingmeans include pivot means at one end of said lever means for mountingsaid fulcrum of said lever means; wherein said first portion is an endportion, located at the other end of said lever means; and wherein saidarmature is connected with said second portion intermediate said ends.

3. Printing needle drive as claimed in claim 1 wherein saidelectromagnetic means includes an annular winding; wherein said armatureis axially movable in said annular winding and has an armature endportion projecting from said winding and directly secured to said secondportion of said lever means.

4. Printing needle drive as claimed in claim 1 wherein said lever meansis a resilient steel rod having said second portion located in a bore insaid armature.

5. Printing needle drive as claimed in claim 1 wherein said printingneedle means includes a wire having a projecting printing end portion,and a resilient attaching end portion attached to said first portion ofsaid lever means so that said wire is resiliently secured to said levermeans.

6. Printing needle drive as claimed in claim 5 wherein said resilientattaching portion of said wire is wound to form a coil tightlysurrounding said first portion of said lever means so that said printingend portion of said wire is resiliently secured to said lever means.

7. Printing needle drive as claimed in claim 2 wherein the thickness andrigidity of said wire is selected so that at least the first turn ofsaid coil resiliently spreads and increases the diameter thereof whensaid projecting printing end portion abuts a printing surface at the endof said needle stroke.

8. Printing needle drive comprising support means; lever means having afulcrum mounted on said supporting means and an end portion oppositesaid fulcrum; printing needle means including a wire having a printingend portion projecting transversely from said end portion of said levermeans and a resilient attaching end portion forming a coil tightlysurrounding said end portion of said lever means so that printing endportion is resiliently secured to said lever means; an oscillationsupressing jacket consisting of synthetic material and enveloping saidcoil, said end portion in said coil, and a portion of said wire adjacentsaid coil; and electromagnetic means including a movable armatureconnected with a second portion of said lever means spaced from saidfulcrum a smaller distance than said end portion so that when saidarmature is moved in an armature stroke of predetermined length, saidneedle means is moved in a needle stroke of proportionally greaterlength, and at a higher speed than said arma' ture.

9. Printing needle drive as claimed in claim 8, wherein said lever meansis resilient, and including stop means on said supporting means forstopping said armature at the end of said armature stroke; and a dampingmember mounted on said support means adjacent said end portion of saidlever means and on the side thereof opposite the side from which saidprinting end portion of said needle means projects, said damping memberbeing engaged with said jacket when said lever means reverses andresiliently returns to the initial postion thereof after said needlemeans has performed said needle stroke.

10. Printing needle drive as claimed in claim 8 wherein said coil has anaxis; wherein said wire includes an intermediate portion between saidprinting end portion and said coil, said printing end portion beingstraight and being located in an imaginary line passing through saidaxis of said coil, and said intermediate portion being cranked out ofsaid line and extending tangentially to the first turn of said coil.

ll. Printing needle drive comprising supporting means;

resilient lever means having a fulcrum mounted on said supporting means;printing needle means secured to a first portion of said lever means andprojecting therefrom transversely to said lever means; electromagneticmeans including a movable armature connected with a second portion ofsaid lever means spaced from said fulcrum a smaller distance than saidfirst portion so that when said armature is moved in an armature strokeof predetermined length, said needle means is moved in a needle strokeof proportionally greater length, and at a higher speed than saidarmature, the mass of said needle means having a predetermined magnitudeto prevent movement of said first portion of said lever means during thefirst part of said armature stroke whereby said lever means isresiliently deformed and tensioned so that said resilient lever meansrecoils during the second part of said armature stroke and acceleratessaid lever means faster than said armature is accelerated when saidelectromagnet means is energized; and an elongated return springextending in the general direction of said lever means, abutting in theregion of opposite ends thereof against said supporting means, and beingconnected between the ends to said armature so as to be resiliently bentwhen said armature performs said armature stroke to thus return saidarmature to a rest position after deenergizing said electromagneticmeans,

12. Printing needle drive as claimed in claim 1], and includingadjustable stop means mounted on said supporting means and engaging saidarmature when the latter is returned by said return spring to said restposition.

13. Printing needle drive comprising supporting means; resilient levermeans having a fulcrum mounted on said supporting means; printing needlemeans so cured to a first portion of said lever means and projectingtherefrom transversely to said lever means; and electromagnetic meansincluding a movable armature connected with a second portion of saidlever means spaced from said fulcrum a smaller distance than said firstportion so that when said armature is moved in an armature stroke ofpredetermined length, said needle means is moved in a needle stroke ofproportionally greater length, and at a higher speed than said armature,the mass of said needle means having a predetermined magnitude toprevent movement of said first portion of said lever means during thefirst part of said armature stroke whereby said resilient means isresiliently deformed and tensioned so that said resilient lever meansrecoils during the second part of said armature stroke and acceleratessaid needle means faster than said armature is accelerated when saidelectromagnet means is energized, said supporting means including stopmeans for stopping said armature at the end of said armature stroke sothat said recoiling resilient lever means continues to move said needlemeans in a free needle stroke after said stop means has stopped saidarmature, and said supporting means including further a damping memberlocated adjacent said first portion on the side of said lever meansremote from said needle means, and being engaged by said first portionwhen said lever means reverses and resiliently returns to the initialposition thereof after performing said free needle stroke,

1. Printing needle drive comprising supporting means; elongated levermeans having a fulcrum mounted on said supporting means and being formedover the whole length thereof from resilient material; printing needlemeans secured to a first portion of said lever means and projectingtherefrom transversely to said lever means; and electromagnetic meansincluding a movable armature connected with a second portion of saidlever means spaced from said fUlcrum a smaller distance than said firstportion so that when said armature is moved in an armature stroke ofpredetermined length, said needle means is moved in a needle stroke ofproportionally greater length, and at a higher speed than said armature,the mass of said needle means having a predetermined magnitude toprevent movement of said first portion of said lever means during thefirst part of said armature stroke whereby said resilient lever means isresiliently deformed and tensioned so that said resilient lever meansrecoils during the second part of said armature stroke and acceleratessaid needle means faster than said armature is accelerated when saidelectromagnet means is energized.
 2. Printing needle drive as claimed inclaim 1 wherein said supporting means include pivot means at one end ofsaid lever means for mounting said fulcrum of said lever means; whereinsaid first portion is an end portion, located at the other end of saidlever means; and wherein said armature is connected with said secondportion intermediate said ends.
 3. Printing needle drive as claimed inclaim 1 wherein said electromagnetic means includes an annular winding;wherein said armature is axially movable in said annular winding and hasan armature end portion projecting from said winding and directlysecured to said second portion of said lever means.
 4. Printing needledrive as claimed in claim 1 wherein said lever means is a resilientsteel rod having said second portion located in a bore in said armature.5. Printing needle drive as claimed in claim 1 wherein said printingneedle means includes a wire having a projecting printing end portion,and a resilient attaching end portion attached to said first portion ofsaid lever means so that said wire is resiliently secured to said levermeans.
 6. Printing needle drive as claimed in claim 5 wherein saidresilient attaching portion of said wire is wound to form a coil tightlysurrounding said first portion of said lever means so that said printingend portion of said wire is resiliently secured to said lever means. 7.Printing needle drive as claimed in claim 2 wherein the thickness andrigidity of said wire is selected so that at least the first turn ofsaid coil resiliently spreads and increases the diameter thereof whensaid projecting printing end portion abuts a printing surface at the endof said needle stroke.
 8. Printing needle drive comprising supportmeans; lever means having a fulcrum mounted on said supporting means andan end portion opposite said fulcrum; printing needle means including awire having a printing end portion projecting transversely from said endportion of said lever means and a resilient attaching end portionforming a coil tightly surrounding said end portion of said lever meansso that printing end portion is resiliently secured to said lever means;an oscillation supressing jacket consisting of synthetic material andenveloping said coil, said end portion in said coil, and a portion ofsaid wire adjacent said coil; and electromagnetic means including amovable armature connected with a second portion of said lever meansspaced from said fulcrum a smaller distance than said end portion sothat when said armature is moved in an armature stroke of predeterminedlength, said needle means is moved in a needle stroke of proportionallygreater length, and at a higher speed than said armature.
 9. Printingneedle drive as claimed in claim 8, wherein said lever means isresilient, and including stop means on said supporting means forstopping said armature at the end of said armature stroke; and a dampingmember mounted on said support means adjacent said end portion of saidlever means and on the side thereof opposite the side from which saidprinting end portion of said needle means projects, said damping memberbeing engaged with said jacket when said lever means reverses andresiliently returns to the initial postion thereof after said needlemeans has perfoRmed said needle stroke.
 10. Printing needle drive asclaimed in claim 8 wherein said coil has an axis; wherein said wireincludes an intermediate portion between said printing end portion andsaid coil, said printing end portion being straight and being located inan imaginary line passing through said axis of said coil, and saidintermediate portion being cranked out of said line and extendingtangentially to the first turn of said coil.
 11. Printing needle drivecomprising supporting means; resilient lever means having a fulcrummounted on said supporting means; printing needle means secured to afirst portion of said lever means and projecting therefrom transverselyto said lever means; electromagnetic means including a movable armatureconnected with a second portion of said lever means spaced from saidfulcrum a smaller distance than said first portion so that when saidarmature is moved in an armature stroke of predetermined length, saidneedle means is moved in a needle stroke of proportionally greaterlength, and at a higher speed than said armature, the mass of saidneedle means having a predetermined magnitude to prevent movement ofsaid first portion of said lever means during the first part of saidarmature stroke whereby said lever means is resiliently deformed andtensioned so that said resilient lever means recoils during the secondpart of said armature stroke and accelerates said lever means fasterthan said armature is accelerated when said electromagnet means isenergized; and an elongated return spring extending in the generaldirection of said lever means, abutting in the region of opposite endsthereof against said supporting means, and being connected between theends to said armature so as to be resiliently bent when said armatureperforms said armature stroke to thus return said armature to a restposition after deenergizing said electromagnetic means.
 12. Printingneedle drive as claimed in claim 11, and including adjustable stop meansmounted on said supporting means and engaging said armature when thelatter is returned by said return spring to said rest position. 13.Printing needle drive comprising supporting means; resilient lever meanshaving a fulcrum mounted on said supporting means; printing needle meanssecured to a first portion of said lever means and projecting therefromtransversely to said lever means; and electromagnetic means including amovable armature connected with a second portion of said lever meansspaced from said fulcrum a smaller distance than said first portion sothat when said armature is moved in an armature stroke of predeterminedlength, said needle means is moved in a needle stroke of proportionallygreater length, and at a higher speed than said armature, the mass ofsaid needle means having a predetermined magnitude to prevent movementof said first portion of said lever means during the first part of saidarmature stroke whereby said resilient means is resiliently deformed andtensioned so that said resilient lever means recoils during the secondpart of said armature stroke and accelerates said needle means fasterthan said armature is accelerated when said electromagnet means isenergized, said supporting means including stop means for stopping saidarmature at the end of said armature stroke so that said recoilingresilient lever means continues to move said needle means in a freeneedle stroke after said stop means has stopped said armature, and saidsupporting means including further a damping member located adjacentsaid first portion on the side of said lever means remote from saidneedle means, and being engaged by said first portion when said levermeans reverses and resiliently returns to the initial position thereofafter performing said free needle stroke.